Implantable meshes made from non-resorbable fibers, such as polypropylene and polyester, are well known in the prior art and are widely used in soft tissue repair. Implantable meshes made from resorbable fibers, or combinations of resorbable fibers and non-resorbable fibers, are also known in the prior art. For example, resorbable meshes, made from poly-4-hydroxybutyrate (P4HB), have been disclosed by Martin et al. J. Surg. Res. 184:766-773 (2013). Implantable meshes are used in procedures such as hernia repair, tendon and ligament repair, mastopexy, pelvic floor reconstruction, and treatment of urinary incontinence. The implantable meshes may be made from either monofilament fibers or multifilament fibers, or they may be made from both types of fibers. Multifilament meshes are generally softer and more compliant than monofilament meshes, however, surgeons often prefer to use monofilament meshes due to higher risks of bacterial contamination associated with the use of multifilament mesh.
Implantable meshes coated with collagen are also known in the art. Collagen coatings can be used to improve cell attachment to an implant, increase cell density on or in an implant, encourage tissue in-growth, increase revascularization, and improve incorporation of the implant in soft tissue. For example, collagen coatings can promote in-growth of fibroblasts and endothelial cells. Improved cell attachment and tissue in-growth can be particularly important in applications where it is desirable to reduce loss of strength during the early healing process. By encouraging earlier or more rapid tissue in-growth, collagen coatings can improve the short-term mechanical support provided by an implant. In addition to using collagen coatings as scaffolds to improve tissue in-growth, collagen coatings can also be used as matrices for delivery of bioactive agents. For example, collagen coatings on meshes can be used as matrices to deliver antimicrobial agents from implantable meshes.
One potential disadvantage of completely coating a mesh with a collagen coating is the possible formation of fluid pockets. These pockets can form, for example, at the site of soft tissue repair between the implant and the soft tissue, and interfere with tissue in-growth into the mesh and remodeling at the implant site.
WO 2011/119742 to Martin et al. discloses methods to completely encapsulate polyhydroxyalkanoate (PHA) mesh with collagen. The encapsulated mesh is prepared by immersing the PHA mesh in a collagen suspension, and drying. The process may be repeated to build up the thickness of the collagen coating on the mesh.
U.S. Pat. No. 3,276,448 to Kronenthal discloses methods of forming prostheses formed of porous, non-absorbable fabric coated with collagen. The methods, however, involve coating a porous fabric with collagen, and subsequently removing collagen from the pores of the fabric by directing a stream of an inert gas against the coated fabric, or alternatively, perforating the collagen coated fabric after the collagen has dried. In the former case, however, the method could result in too much collagen being stripped from the fabric or too little, and it is difficult to control the thickness of the collagen coating. In the latter case, perforating a collagen-coated fabric can result in damage to the underlying fabric resulting in decreased mechanical strength of the fabric.
It would therefore be desirable to identify a method to produce perforated collagen coated meshes that prevent the formation of fluid pockets and are more readily incorporated into host tissue. It would also be desirable to identify a method to produced perforated collagen coated meshes with defined coating thickness, and defined pore sizes and porosity.
It is therefore an object of the invention to provide a method to prepare a perforated collagen coated surgical mesh, without damaging the surface of the surgical mesh or its mechanical properties, and which affords control of the thickness of the collagen coating.
It is another object of the invention to provide an implant including a collagen-coated mesh with perforations that are formed through the pores of the mesh.
It is yet another objection of the invention to provide an implant for soft or hard tissue repair, wherein the implant comprises a collagen-coated mesh with perforations.
It is still a further object of the invention to provide methods to implant perforated collagen-coated meshes.